Pore Pressure Drop During Dynamic Rupture and Conditions for Dilatancy Hardening

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985858%3A_____%2F23%3A00573882" target="_blank" >RIV/67985858:_____/23:00573882 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/44555601:13440/23:43897742

Výsledek na webu

<a href="https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2023JB026396?src=getftr" target="_blank" >https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2023JB026396?src=getftr</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2023JB026396" target="_blank" >10.1029/2023JB026396</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Pore Pressure Drop During Dynamic Rupture and Conditions for Dilatancy Hardening

Popis výsledku v původním jazyce

Pore pressure drop brought about by fault dilatancy during accelerating slip may suppress nucleation of earthquakes. Yet, direct measurements of pore pressure during dynamic slip are challenging to produce. We present results of a physics-based model simulating onset of slip in saturated granular layers coupled to a constant fluid pressure reservoir. Grain rearrangements required for slip to commence induce incipient rapid dilatation during which the maximum pore pressure drop is generated. We find that up to a critical slip rate the pore pressure drop is consistent with a prediction derived for an incompressible fluid flow. In this drained regime, excess pore pressure is efficiently relaxed and has little effect on slip stability. Above the critical slip rate, marking the onset of undrained conditions, the pore pressure drop decays slowly, inhibits dilatation rate, and significantly increases strength of the layer, stabilizing the rupture growth. The magnitude of the pore pressure drop increases monotonically with the drainage number given as the ratio of the dilatation rate to a characteristic fluid infiltration rate. The pore pressure drop in the undrained regime also depends on a second non-dimensional parameter, urn:x-wiley:21699313:media:jgrb56355:jgrb56355-math-0001, where β is storage capacity, and urn:x-wiley:21699313:media:jgrb56355:jgrb56355-math-0002 is the effective normal stress. Low values of this parameter enhance localization of strain near the drained boundaries of the layer, promoting fluid flow into the layer. Our results can be used to better constrain drainage conditions associated with changes in slip rate, the magnitude of the generated pore pressure and the corresponding fault strengthening.

Název v anglickém jazyce

Pore Pressure Drop During Dynamic Rupture and Conditions for Dilatancy Hardening

Popis výsledku anglicky

Pore pressure drop brought about by fault dilatancy during accelerating slip may suppress nucleation of earthquakes. Yet, direct measurements of pore pressure during dynamic slip are challenging to produce. We present results of a physics-based model simulating onset of slip in saturated granular layers coupled to a constant fluid pressure reservoir. Grain rearrangements required for slip to commence induce incipient rapid dilatation during which the maximum pore pressure drop is generated. We find that up to a critical slip rate the pore pressure drop is consistent with a prediction derived for an incompressible fluid flow. In this drained regime, excess pore pressure is efficiently relaxed and has little effect on slip stability. Above the critical slip rate, marking the onset of undrained conditions, the pore pressure drop decays slowly, inhibits dilatation rate, and significantly increases strength of the layer, stabilizing the rupture growth. The magnitude of the pore pressure drop increases monotonically with the drainage number given as the ratio of the dilatation rate to a characteristic fluid infiltration rate. The pore pressure drop in the undrained regime also depends on a second non-dimensional parameter, urn:x-wiley:21699313:media:jgrb56355:jgrb56355-math-0001, where β is storage capacity, and urn:x-wiley:21699313:media:jgrb56355:jgrb56355-math-0002 is the effective normal stress. Low values of this parameter enhance localization of strain near the drained boundaries of the layer, promoting fluid flow into the layer. Our results can be used to better constrain drainage conditions associated with changes in slip rate, the magnitude of the generated pore pressure and the corresponding fault strengthening.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GJ19-21114Y" target="_blank" >GJ19-21114Y: Mechanická teorie dynamicky aktivovaných zemětřesení</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Geophysical Research-Solid Earth

ISSN

2169-9313

e-ISSN

2169-9356

Svazek periodika

128

Číslo periodika v rámci svazku

7

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

30

Strana od-do

e2023JB026396

Kód UT WoS článku

001042049100001

EID výsledku v databázi Scopus

2-s2.0-85164031833